Norwegian Cyclone Model

If you track low pressure areas and fronts you will often notice a particular cycle these systems undergo. The Norwegian cyclone model, so named to honor the Norwegian meteorologists who first conceptualized the typical life cycle of cyclones in the 1910s and 1920s.

Initial Condition

In this model, there will initially be a boundary, or front, separating warm air to the south from cold air to the north. The front is often stationary.

Norwegian cyclone model initial stage - weather map view

Norwegian cyclone model initial stage - 3D view

Beginning Stage

A wave develops on the front as an upper level low pressure system, embedded in the jet stream moves, over the front. The front develops a "kink" where the wave is developing. The stationary front changes into a cold front and warm front as the air masses begin to move. Precipitation will begin to develop with the heaviest occurrence along the front (dark green).

Wave forms on front - weather map view

Wave forms on front - 3D view

Intensification

As the wave intensifies, both cold and warm fronts become better organized.

Wave intensifies - overhead view

Wave intensifies - 3D view

Mature Stage

The wave becomes a mature low pressure system, while the cold front, moving faster than the warm front, "catches up" with the warm front. As the cold front overtakes the warm front, an occluded front forms.

A mature low pressure system - overhead view

A mature low pressure system - 3D view

Dissipation

As the cold front continues advancing on the warm front, the occlusion increases and eventually cuts off the supply of warm moist air, causing the low pressure system to gradually dissipate.